Possible main sources of coronavirus in PH identified

Metro Manila (CNN Philippines, August 27) — Filipino researchers have found three possible main sources of coronavirus infection in the country.

In a paper published in the medRxiv preprint website on Tuesday, the Philippine Genome Center said the following groups could probably be the primary sources of the virus:

- The foreign tourists with travel history to China's Wuhan City - the epicenter of the COVID-19 outbreak early this year -- whose samples were collected in January

- Repatriated seafarers from the coronovirus-hit M/V Diamond Princess in Japan whose samples were taken in March

- Evacuated tourists and overseas Filipino workers who arrived in May from Europe and the Middle East whose samples were collected in June

The first three confirmed cases in the Philippines were Chinese tourists from Wuhan. They were found to be positive for coronavirus in late January. Two of them flew back to China, while the other one died of COVID-19 in the country in early February.

In a study released last week, the Research Institute for Tropical Medicine said that the gene sequence of the three Chinese tourists was different from the rest of the samples that they studied. Sequence data are used to determine how the virus spreads in the community, RITM explained.

But Department of Health spokesperson Maria Rosario Vergeire was quick to clarify that this finding is not “conclusive” and should be interpreted with caution as it is based on a small sample of positive cases.

“We need to further study so that we can accurately say that the Chinese [tourists] weren’t the ones who spread [the virus] and that we had other sources of our infection,” she added.

From three cases, the number of infections in the Philippines reached 100 in mid-March.

On February 26, the government brought home 440 crew members and passengers from the cruise ship, who went through a 14-day quarantine at the Athlete's Village in New Clark City, Tarlac.

The genome center said they saw cases of community transmissions in patients admitted to the Philippine General Hospital whose swab samples were taken between March 22 to 26, 10 days after the evacuated seafarers and passengers completed their quarantine.

It pointed out that the PGH patients have had no known travel history to a country with cases of community transmission, and no known exposure to a confirmed case in March. The genome center said that these suggest that they may have acquired the infection from undetected cases among the repatriated seafarers.

The findings, which were based on the analysis of 1,335 SARS-CoV-2 sequences, have not undergone peer review, a process that vets study results.

But PGC underscored the need to “continually review and improve the quarantine, testing and tracing measures being employed to adapt to the current pandemic situation."

Earlier this month, the PGC detected a mutated strain of coronavirus in a small sample of positive cases taken from Quezon City in June. The new mutation of the SARS-CoV-2 virus called G614 was found by international researchers to be more infectious but does not make people more severely sick. G614 has been previously found in parts of Europe.

The country now has over 200,000 cases, with 3,137 deaths and 133,460 recoveries.